Positron Binding Properties of Glycine and Its Aqueous Complexes

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• 作者：Mikko Nummela ; Hannes Raebiger ; Daisuke Yoshida ; Masanori Tachikawa
• 刊名：Journal of Physical Chemistry A
• 出版年：2016
• 出版时间：June 16, 2016
• 年：2016
• 卷：120
• 期：23
• 页码：4037-4042
• 全文大小：354K
• 年卷期：0
• ISSN：1520-5215

文摘

We investigate positron binding to glycine and its aqueous complexes by first-principles calculation. We show that while glycine in its ground state (Gly) does not bind positrons, several of its strongly polar conformers do, and in particular, its zwitterion form (GlyZI) binds positrons strongly. Aqueous complexes Gly·nH₂O and GlyZI·nH₂O also bind positrons, if their dipole moment μ > μ_cr. However, μ is not a sufficient quantity to describe positron binding to these complexes. We show that in addition to μ, positron binding strongly depends on the intramolecular bonding of glycine. In Gly·nH₂O, positrons are weakly bound to the nitrogen in Gly, whereas in GlyZI·nH₂O, the ionic oxygen in GlyZI is a strong “positron attractor”.